A Study of Two Dose Levels of Vobramitamab Duocarmazine in Participants With Metastatic Castration Resistant Prostate Cancer

Inclusion Criteria:

Histologically confirmed adenocarcinoma of the prostate without evidence of neuroendocrine differentiation, signet cell, or small cell features.
Participants must have ≥ 1 metastatic lesion that is present on magnetic resonance imaging (MRI), computed tomography (CT), or bone scan obtained ≤ 28 days prior to initiation of study treatment.
Tumor progression at study entry documented by PSA or imaging per PCWG3 criteria
Received 1 prior ARAT for metastatic or non-metastatic, castration-sensitive or castration-resistant prostate cancer. A second ARAT regimen of <60 days used as bridging to lutetium-177 is permitted.
Availability of archival or formalin-fixed paraffin-embedded (FFPE) tumor tissue sample for participants with metastasis to internal organs
Acceptable physical condition and laboratory values.

Exclusion Criteria:

Any underlying medical or psychiatric condition impairing participant's ability to receive, tolerate, or comply with the planned treatment or study procedures.
Received >1 prior taxane-containing regimen for prostate cancer. A second taxane regimen of <60 days used as bridging for lutetium-177 is permitted.
Received >3 total prior therapies for mCRPC
Participants with known BRCA or ATM mutation (germline or somatic) are not eligible unless they received prior treatment with a PARP inhibitor where available, indicated and tolerated.
Another hematologic or solid tumor ≥ stage 1 malignancy that completed surgery, last dose of radiotherapy, or last dose of systemic anti-cancer therapy ≤ 2 years from first dose of study treatment. Participants who had curative therapy for non-melanomatous skin cancer or for localized malignancy are eligible.
Untreated, symptomatic central nervous system (CNS) metastasis.
Prior treatment with any B7-H3 targeted agent for cancer,
Contradictions to the use of corticosteroid treatment
Prior stem cell, tissue, or solid organ transplant.
Use of products that have published anti-prostate cancer activity or are known to decrease PSA.